Catalogue of the hymenopterous insects in the collection of the British Museum. Part VI. Formicidae. Author Smith, F. text 1858 British Museum London http://antbase.org/ants/publications/8127/8127.pdf book 8127 C86CFDBF-61D9-48EE-9C2E-325FC0462B10 158. Formica stigma . Formica stigma, Fabr. Syst. Piez. 400. 18. Hab. South America. This is probably an Odontomachus ; the black stigma is characteristic of all the species, and the exserted mandibles are equally constant in that genus.